Conductive lines and vias are commonly used as interconnect structures to form an integrated circuit of a semiconductor device. Vias are used to connect conductive lines formed on multiple levels of interconnect layers.
In addition, through silicon vias (TSVs) are formed through the silicon substrate for coupling multiple integrated circuit chips to form a stacked semiconductor device. Such a stacked semiconductor device is formed to provide an integrated circuit with high capacity and low area.
With any type of via, a conductive line is desired to be formed onto the via with high quality of contact. Such a high quality contact is desired for connection between the via and the conductive line with low resistance and high current capacity.